1. Field of the Invention
This invention relates to a material handling structure or assembly typically known as a clamshell-type device which is operated by and movably supported for operative positioning relative to material being handled and transferred by means of a helicopter itself being equipped to operate opening and closing of the clamshell structure through control components adapted to be mounted on the helicopter.
2. Description of the Prior Art
Clamshell-type structures are commonly known for material handling and more specifically wherein any type of applicable material, sand, gravel, rocks, etc. can be transferred from one location to another. The prior art is replete with various clamshell structures primarily which are designed to be used in a substantially conventional manner from crane powered winches, etc. Such structures are disclosed in the Dreeson, U.S. Pat. No. 4,364,704. This patent discloses a grab bucket in the form of a clamshell device suspended from a cable wherein the cable is associated and used in combination with a hoisting means having a reversible motor drive means to raise and lower the grab bucket relative to the material being handled.
Similarly Ferwerda, U.S. Pat. No. 3,041,755, discloses a clamshell-type bucket having specific structural features including a pair of tiltable bucket sections adapted to close upon each other in jaw like, grabbing motion to effect handling of the material and placing it within the grab bucket in a "scooping" type fashion. An important feature of the device disclosed therein is an improved closing motion directed to the clamshell bucket section.
Stone, U.S. Pat. No. 3,199,008, discloses a plural motor speed control for the operation of a grab bucket again in the form of a clamshell-type structure.
Also Wetherbee, U.S. Pat. No. 3,762,078. discloses a dredge structure generally in the form of what is known as a clamshell-type bucket especially adapted for taking samples from the bottom of a body of water wherein the structure comprises a hollow body open at its top and bottom but provided at both its top and bottom with closures movable between an open and a closed position and biased normally into their closed positions.
As set forth in the above noted patents and as is generally recognized in the prior art relating to this subject matter, most of the grab buckets or clamshell-type structures referred to are operated by an electrically powered winch or cable and pulley assembly normally associated with some type of crane or other similar type positioning support structure which is intended to operate in a substantially stationary location. Of course, it is acknowledged that certain of the crane type support structures are portable to the extent of being moved from one location to another. The majority of the grab buckets in the form of the clamshell-type structure are generally considered located in combination with the structure at a substantially fixed location or building site.
The above noted patents do not disclose or even suggest the use of a material handling device in the form of the aforementioned category of grab buckets being support from and operated by a portable support base or platform such as a helicopter.
However, the Bannister, U.S. Pat. No. 2,717,656, discloses a method and apparatus for use in surveying earth formation by explosion and seismograph wherein a probe type element is carried by and suspended from a helicopter and operatively disposed into the intended position again through the use of apparently a hoist type mechanism or the like. Similarly, the Huested, U.S. Pat. No. 3,730,398, discloses one or more helicopters associated with a specific lift rig or assembly for the airlifting of relatively large devices such as jeeps or the like.
None of the above noted patents specifically discloses the variety of operation and therefore increased utility of a grab bucket in the form of a clamshell-type structure specifically designed and adapted to be suspended from, positioned by and operated through specified control associated with a helicopter assembly wherein the entire material handling assembly associated with the helicopter can effectively be adapted to almost any commercially available and currently manufactured helicopter vehicle.